Lower grille blocking for fuel economy gains

Engineer's note on grille blanking: adiabatic cooling effect should not be discounted i.e. a narrow slit in a high pressure area, allowing air through which then is forced to expand, thereby lowing its temperature.
Done well, you can have the aerodynamic benefits without compromising the cooling system.
 
I have taken a similar approach to @gills however with mine I made the blanking cover out of 0.5 mm black polypropylene (like the material that plastic ring binders are made from), this meant that I could fold the top and bottom over the sides of the grille. With the bits that are folded over the top and bottom I cut v shapes out of it so that the curved profile of the grille could be maintained. I then attached these folded over tabs with some 3M VHB tape to stop it being able to get pulled off the car and to keep it looking smooth. This material that I have used has a similar textured finish to what the lower plastic trim has. It still doesn't exactly look OEM though but does seem to be pretty effective.

I am sure that there would be a way of fitting something stronger from behind like the blanking plate that the FSI's have where the charge cooler is on the TDI cars however that was beyond my creativity and materials that I had in the garage.
 
What would you suggest then?
I would go with test and re-evaluate approach. A single horizontal slit at the top (air temps are highest the closer you get to the tarmac) and see how it performs. If its insufficient or tdi performance suffers, widen the slit.
 
I have taken a similar approach to @gills however with mine I made the blanking cover out of 0.5 mm black polypropylene (like the material that plastic ring binders are made from), this meant that I could fold the top and bottom over the sides of the grille. With the bits that are folded over the top and bottom I cut v shapes out of it so that the curved profile of the grille could be maintained. I then attached these folded over tabs with some 3M VHB tape to stop it being able to get pulled off the car and to keep it looking smooth. This material that I have used has a similar textured finish to what the lower plastic trim has. It still doesn't exactly look OEM though but does seem to be pretty effective.

I am sure that there would be a way of fitting something stronger from behind like the blanking plate that the FSI's have where the charge cooler is on the TDI cars however that was beyond my creativity and materials that I had in the garage.
Can you share some close up links? Thanks!
 
Can you share some close up links? Thanks!
I will try and take some pictures tomorrow in the light. I have to warn you that it is not super pretty as my first attempt was made out of two pieces of PP sheet so there's an annoying seam up the middle. I do plan to get a larger sheet so that I can make it all out of one piece and on this one I will make the cut out for the ambient temperature sensor have round corners to minimise the risk of it tearing from this hole.
 
Can you share some close up links? Thanks!

Here we go. Like I said not super pretty but effective. The seam really annoys me so definitely would recommend making it out of one piece rather than two. Will be keeping an eye on temperatures as the weather starts warming up, in the cold I don't think it makes much or any difference to warm up time.
 

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I think your doing yourself a disservice as it actually looks pretty good to me!

Fancy making another set in exchange for a contribution for your efforts?!
 
I think your doing yourself a disservice as it actually looks pretty good to me!

Fancy making another set in exchange for a contribution for your efforts?!
Thanks, if I can source some larger sheets of suitable material I'll get some extra as the postage cost is far more than the material cost on most sites and see about iterating the design and then I'll get back to this thread with an update.
 
I’d be up for a group buy! I’m sure others would too as long as the intercooler scoop remained open and it was easy to clip on / off.
 
....was hoping one of you would say something really nice about the Elise/340R frame work and in particular the innovative glue process.. since it impressed 9 other brands enough to buy rights use it too.... ? ? ??

Ahem... Innovative procecesses might be found here... ?


???
 
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